--- jsr166/src/main/java/util/NavigableMap.java 2005/05/18 01:39:35 1.9 +++ jsr166/src/main/java/util/NavigableMap.java 2013/03/09 01:51:15 1.28 @@ -1,7 +1,7 @@ /* - * Written by Doug Lea with assistance from members of JCP JSR-166 - * Expert Group and released to the public domain, as explained at - * http://creativecommons.org/licenses/publicdomain + * Written by Doug Lea and Josh Bloch with assistance from members of JCP + * JSR-166 Expert Group and released to the public domain, as explained at + * http://creativecommons.org/publicdomain/zero/1.0/ */ package java.util; @@ -9,45 +9,56 @@ package java.util; /** * A {@link SortedMap} extended with navigation methods returning the * closest matches for given search targets. Methods - * lowerEntry, floorEntry, ceilingEntry, - * and higherEntry return Map.Entry objects + * {@link #lowerEntry}, {@link #floorEntry}, {@link #ceilingEntry}, + * and {@link #higherEntry} return {@code Map.Entry} objects * associated with keys respectively less than, less than or equal, * greater than or equal, and greater than a given key, returning - * null if there is no such key. Similarly, methods - * lowerKey, floorKey, ceilingKey, and - * higherKey return only the associated keys. All of these + * {@code null} if there is no such key. Similarly, methods + * {@link #lowerKey}, {@link #floorKey}, {@link #ceilingKey}, and + * {@link #higherKey} return only the associated keys. All of these * methods are designed for locating, not traversing entries. * - *

A NavigableMap may be viewed and traversed in either - * ascending or descending key order. The Map methods - * keySet and entrySet return ascending views, and - * the additional methods descendingKeySet and - * descendingEntrySet return descending views. The - * performance of ascending traversals is likely to be faster than - * descending traversals. Notice that it is possible to perform - * subrange traversals in either direction using navigableSubMap. - * Methods navigableSubMap, navigableHeadMap, and - * navigableTailMap differ from the similarly named - * SortedMap methods only in that the returned maps - * are guaranteed to obey the NavigableMap interface. + *

A {@code NavigableMap} may be accessed and traversed in either + * ascending or descending key order. The {@code descendingMap} + * method returns a view of the map with the senses of all relational + * and directional methods inverted. The performance of ascending + * operations and views is likely to be faster than that of descending + * ones. Methods {@code subMap}, {@code headMap}, + * and {@code tailMap} differ from the like-named {@code + * SortedMap} methods in accepting additional arguments describing + * whether lower and upper bounds are inclusive versus exclusive. + * Submaps of any {@code NavigableMap} must implement the {@code + * NavigableMap} interface. * - *

This interface additionally defines methods firstEntry, - * pollFirstEntry, lastEntry, and - * pollLastEntry that return and/or remove the least and - * greatest mappings, if any exist, else returning null. + *

This interface additionally defines methods {@link #firstEntry}, + * {@link #pollFirstEntry}, {@link #lastEntry}, and + * {@link #pollLastEntry} that return and/or remove the least and + * greatest mappings, if any exist, else returning {@code null}. * - *

Implementations of entry-returning methods are expected to - * return Map.Entry pairs representing snapshots of mappings + *

Implementations of entry-returning methods are expected to + * return {@code Map.Entry} pairs representing snapshots of mappings * at the time they were produced, and thus generally do not - * support the optional Entry.setValue method. Note however + * support the optional {@code Entry.setValue} method. Note however * that it is possible to change mappings in the associated map using - * method put. + * method {@code put}. + * + *

Methods + * {@link #subMap(Object, Object) subMap(K, K)}, + * {@link #headMap(Object) headMap(K)}, and + * {@link #tailMap(Object) tailMap(K)} + * are specified to return {@code SortedMap} to allow existing + * implementations of {@code SortedMap} to be compatibly retrofitted to + * implement {@code NavigableMap}, but extensions and implementations + * of this interface are encouraged to override these methods to return + * {@code NavigableMap}. Similarly, + * {@link #keySet()} can be overridden to return {@code NavigableSet}. * *

This interface is a member of the - * + * * Java Collections Framework. * * @author Doug Lea + * @author Josh Bloch * @param the type of keys maintained by this map * @param the type of mapped values * @since 1.6 @@ -55,12 +66,12 @@ package java.util; public interface NavigableMap extends SortedMap { /** * Returns a key-value mapping associated with the greatest key - * strictly less than the given key, or null if there is + * strictly less than the given key, or {@code null} if there is * no such key. * * @param key the key - * @return an entry with the greatest key less than key, - * or null if there is no such key + * @return an entry with the greatest key less than {@code key}, + * or {@code null} if there is no such key * @throws ClassCastException if the specified key cannot be compared * with the keys currently in the map * @throws NullPointerException if the specified key is null @@ -70,11 +81,11 @@ public interface NavigableMap exten /** * Returns the greatest key strictly less than the given key, or - * null if there is no such key. + * {@code null} if there is no such key. * * @param key the key - * @return the greatest key less than key, - * or null if there is no such key + * @return the greatest key less than {@code key}, + * or {@code null} if there is no such key * @throws ClassCastException if the specified key cannot be compared * with the keys currently in the map * @throws NullPointerException if the specified key is null @@ -84,12 +95,12 @@ public interface NavigableMap exten /** * Returns a key-value mapping associated with the greatest key - * less than or equal to the given key, or null if there + * less than or equal to the given key, or {@code null} if there * is no such key. * * @param key the key * @return an entry with the greatest key less than or equal to - * key, or null if there is no such key + * {@code key}, or {@code null} if there is no such key * @throws ClassCastException if the specified key cannot be compared * with the keys currently in the map * @throws NullPointerException if the specified key is null @@ -99,11 +110,11 @@ public interface NavigableMap exten /** * Returns the greatest key less than or equal to the given key, - * or null if there is no such key. + * or {@code null} if there is no such key. * * @param key the key - * @return the greatest key less than or equal to key, - * or null if there is no such key + * @return the greatest key less than or equal to {@code key}, + * or {@code null} if there is no such key * @throws ClassCastException if the specified key cannot be compared * with the keys currently in the map * @throws NullPointerException if the specified key is null @@ -113,12 +124,12 @@ public interface NavigableMap exten /** * Returns a key-value mapping associated with the least key - * greater than or equal to the given key, or null if + * greater than or equal to the given key, or {@code null} if * there is no such key. * * @param key the key * @return an entry with the least key greater than or equal to - * key, or null if there is no such key + * {@code key}, or {@code null} if there is no such key * @throws ClassCastException if the specified key cannot be compared * with the keys currently in the map * @throws NullPointerException if the specified key is null @@ -128,11 +139,11 @@ public interface NavigableMap exten /** * Returns the least key greater than or equal to the given key, - * or null if there is no such key. + * or {@code null} if there is no such key. * * @param key the key - * @return the least key greater than or equal to key, - * or null if there is no such key + * @return the least key greater than or equal to {@code key}, + * or {@code null} if there is no such key * @throws ClassCastException if the specified key cannot be compared * with the keys currently in the map * @throws NullPointerException if the specified key is null @@ -142,12 +153,12 @@ public interface NavigableMap exten /** * Returns a key-value mapping associated with the least key - * strictly greater than the given key, or null if there + * strictly greater than the given key, or {@code null} if there * is no such key. * * @param key the key - * @return an entry with the least key greater than key, - * or null if there is no such key + * @return an entry with the least key greater than {@code key}, + * or {@code null} if there is no such key * @throws ClassCastException if the specified key cannot be compared * with the keys currently in the map * @throws NullPointerException if the specified key is null @@ -157,11 +168,11 @@ public interface NavigableMap exten /** * Returns the least key strictly greater than the given key, or - * null if there is no such key. + * {@code null} if there is no such key. * * @param key the key - * @return the least key greater than key, - * or null if there is no such key + * @return the least key greater than {@code key}, + * or {@code null} if there is no such key * @throws ClassCastException if the specified key cannot be compared * with the keys currently in the map * @throws NullPointerException if the specified key is null @@ -171,161 +182,214 @@ public interface NavigableMap exten /** * Returns a key-value mapping associated with the least - * key in this map, or null if the map is empty. + * key in this map, or {@code null} if the map is empty. * * @return an entry with the least key, - * or null if this map is empty + * or {@code null} if this map is empty */ Map.Entry firstEntry(); /** * Returns a key-value mapping associated with the greatest - * key in this map, or null if the map is empty. + * key in this map, or {@code null} if the map is empty. * * @return an entry with the greatest key, - * or null if this map is empty + * or {@code null} if this map is empty */ Map.Entry lastEntry(); /** * Removes and returns a key-value mapping associated with - * the least key in this map, or null if the map is empty. + * the least key in this map, or {@code null} if the map is empty. * * @return the removed first entry of this map, - * or null if this map is empty + * or {@code null} if this map is empty */ Map.Entry pollFirstEntry(); /** * Removes and returns a key-value mapping associated with - * the greatest key in this map, or null if the map is empty. + * the greatest key in this map, or {@code null} if the map is empty. * * @return the removed last entry of this map, - * or null if this map is empty + * or {@code null} if this map is empty */ Map.Entry pollLastEntry(); /** - * Returns a {@link Set} view of the keys contained in this map. + * Returns a reverse order view of the mappings contained in this map. + * The descending map is backed by this map, so changes to the map are + * reflected in the descending map, and vice-versa. If either map is + * modified while an iteration over a collection view of either map + * is in progress (except through the iterator's own {@code remove} + * operation), the results of the iteration are undefined. + * + *

The returned map has an ordering equivalent to + * {@link Collections#reverseOrder(Comparator) Collections.reverseOrder}{@code (comparator())}. + * The expression {@code m.descendingMap().descendingMap()} returns a + * view of {@code m} essentially equivalent to {@code m}. + * + * @return a reverse order view of this map + */ + NavigableMap descendingMap(); + + /** + * Returns a {@link NavigableSet} view of the keys contained in this map. + * The set's iterator returns the keys in ascending order. + * The set is backed by the map, so changes to the map are reflected in + * the set, and vice-versa. If the map is modified while an iteration + * over the set is in progress (except through the iterator's own {@code + * remove} operation), the results of the iteration are undefined. The + * set supports element removal, which removes the corresponding mapping + * from the map, via the {@code Iterator.remove}, {@code Set.remove}, + * {@code removeAll}, {@code retainAll}, and {@code clear} operations. + * It does not support the {@code add} or {@code addAll} operations. + * + * @return a navigable set view of the keys in this map + */ + NavigableSet navigableKeySet(); + + /** + * Returns a reverse order {@link NavigableSet} view of the keys contained in this map. * The set's iterator returns the keys in descending order. - * The set is backed by the map, so changes to the map are - * reflected in the set, and vice-versa. If the map is modified - * while an iteration over the set is in progress (except through - * the iterator's own remove operation), the results of - * the iteration are undefined. The set supports element removal, - * which removes the corresponding mapping from the map, via the - * Iterator.remove, Set.remove, - * removeAll, retainAll, and clear - * operations. It does not support the add or addAll - * operations. - * - * @return a set view of the keys contained in this map, sorted in - * descending order - */ - Set descendingKeySet(); - - /** - * Returns a {@link Set} view of the mappings contained in this map. - * The set's iterator returns the entries in descending key order. - * The set is backed by the map, so changes to the map are - * reflected in the set, and vice-versa. If the map is modified - * while an iteration over the set is in progress (except through - * the iterator's own remove operation, or through the - * setValue operation on a map entry returned by the - * iterator) the results of the iteration are undefined. The set - * supports element removal, which removes the corresponding - * mapping from the map, via the Iterator.remove, - * Set.remove, removeAll, retainAll and - * clear operations. It does not support the - * add or addAll operations. + * The set is backed by the map, so changes to the map are reflected in + * the set, and vice-versa. If the map is modified while an iteration + * over the set is in progress (except through the iterator's own {@code + * remove} operation), the results of the iteration are undefined. The + * set supports element removal, which removes the corresponding mapping + * from the map, via the {@code Iterator.remove}, {@code Set.remove}, + * {@code removeAll}, {@code retainAll}, and {@code clear} operations. + * It does not support the {@code add} or {@code addAll} operations. * - * @return a set view of the mappings contained in this map, - * sorted in descending key order + * @return a reverse order navigable set view of the keys in this map */ - Set> descendingEntrySet(); + NavigableSet descendingKeySet(); /** * Returns a view of the portion of this map whose keys range from - * fromKey, inclusive, to toKey, exclusive. (If - * fromKey and toKey are equal, the returned map - * is empty.) The returned map is backed by this map, so changes - * in the returned map are reflected in this map, and vice-versa. - * The returned map supports all optional map operations that this - * map supports. - * - *

The returned map will throw an IllegalArgumentException - * on an attempt to insert a key outside its range. + * {@code fromKey} to {@code toKey}. If {@code fromKey} and + * {@code toKey} are equal, the returned map is empty unless + * {@code fromExclusive} and {@code toExclusive} are both true. The + * returned map is backed by this map, so changes in the returned map are + * reflected in this map, and vice-versa. The returned map supports all + * optional map operations that this map supports. * - * @param fromKey low endpoint (inclusive) of the keys in the returned map - * @param toKey high endpoint (exclusive) of the keys in the returned map + *

The returned map will throw an {@code IllegalArgumentException} + * on an attempt to insert a key outside of its range, or to construct a + * submap either of whose endpoints lie outside its range. + * + * @param fromKey low endpoint of the keys in the returned map + * @param fromInclusive {@code true} if the low endpoint + * is to be included in the returned view + * @param toKey high endpoint of the keys in the returned map + * @param toInclusive {@code true} if the high endpoint + * is to be included in the returned view * @return a view of the portion of this map whose keys range from - * fromKey, inclusive, to toKey, exclusive - * @throws ClassCastException if fromKey and toKey + * {@code fromKey} to {@code toKey} + * @throws ClassCastException if {@code fromKey} and {@code toKey} * cannot be compared to one another using this map's comparator * (or, if the map has no comparator, using natural ordering). * Implementations may, but are not required to, throw this - * exception if fromKey or toKey + * exception if {@code fromKey} or {@code toKey} * cannot be compared to keys currently in the map. - * @throws NullPointerException if fromKey or toKey + * @throws NullPointerException if {@code fromKey} or {@code toKey} * is null and this map does not permit null keys - * @throws IllegalArgumentException if fromKey is greater than - * toKey; or if this map itself has a restricted - * range, and fromKey or toKey lies + * @throws IllegalArgumentException if {@code fromKey} is greater than + * {@code toKey}; or if this map itself has a restricted + * range, and {@code fromKey} or {@code toKey} lies * outside the bounds of the range */ - NavigableMap navigableSubMap(K fromKey, K toKey); + NavigableMap subMap(K fromKey, boolean fromInclusive, + K toKey, boolean toInclusive); /** - * Returns a view of the portion of this map whose keys are - * strictly less than toKey. The returned map is backed - * by this map, so changes in the returned map are reflected in - * this map, and vice-versa. The returned map supports all - * optional map operations that this map supports. + * Returns a view of the portion of this map whose keys are less than (or + * equal to, if {@code inclusive} is true) {@code toKey}. The returned + * map is backed by this map, so changes in the returned map are reflected + * in this map, and vice-versa. The returned map supports all optional + * map operations that this map supports. * - *

The returned map will throw an IllegalArgumentException + *

The returned map will throw an {@code IllegalArgumentException} * on an attempt to insert a key outside its range. * - * @param toKey high endpoint (exclusive) of the keys in the returned map - * @return a view of the portion of this map whose keys are strictly - * less than toKey - * @throws ClassCastException if toKey is not compatible + * @param toKey high endpoint of the keys in the returned map + * @param inclusive {@code true} if the high endpoint + * is to be included in the returned view + * @return a view of the portion of this map whose keys are less than + * (or equal to, if {@code inclusive} is true) {@code toKey} + * @throws ClassCastException if {@code toKey} is not compatible * with this map's comparator (or, if the map has no comparator, - * if toKey does not implement {@link Comparable}). + * if {@code toKey} does not implement {@link Comparable}). * Implementations may, but are not required to, throw this - * exception if toKey cannot be compared to keys + * exception if {@code toKey} cannot be compared to keys * currently in the map. - * @throws NullPointerException if toKey is null + * @throws NullPointerException if {@code toKey} is null * and this map does not permit null keys * @throws IllegalArgumentException if this map itself has a - * restricted range, and toKey lies outside the + * restricted range, and {@code toKey} lies outside the * bounds of the range */ - NavigableMap navigableHeadMap(K toKey); + NavigableMap headMap(K toKey, boolean inclusive); /** - * Returns a view of the portion of this map whose keys are - * greater than or equal to fromKey. The returned map is - * backed by this map, so changes in the returned map are - * reflected in this map, and vice-versa. The returned map - * supports all optional map operations that this map supports. + * Returns a view of the portion of this map whose keys are greater than (or + * equal to, if {@code inclusive} is true) {@code fromKey}. The returned + * map is backed by this map, so changes in the returned map are reflected + * in this map, and vice-versa. The returned map supports all optional + * map operations that this map supports. * - *

The returned map will throw an IllegalArgumentException + *

The returned map will throw an {@code IllegalArgumentException} * on an attempt to insert a key outside its range. * - * @param fromKey low endpoint (inclusive) of the keys in the returned map - * @return a view of the portion of this map whose keys are greater - * than or equal to fromKey - * @throws ClassCastException if fromKey is not compatible + * @param fromKey low endpoint of the keys in the returned map + * @param inclusive {@code true} if the low endpoint + * is to be included in the returned view + * @return a view of the portion of this map whose keys are greater than + * (or equal to, if {@code inclusive} is true) {@code fromKey} + * @throws ClassCastException if {@code fromKey} is not compatible * with this map's comparator (or, if the map has no comparator, - * if fromKey does not implement {@link Comparable}). + * if {@code fromKey} does not implement {@link Comparable}). * Implementations may, but are not required to, throw this - * exception if fromKey cannot be compared to keys + * exception if {@code fromKey} cannot be compared to keys * currently in the map. - * @throws NullPointerException if fromKey is null + * @throws NullPointerException if {@code fromKey} is null * and this map does not permit null keys * @throws IllegalArgumentException if this map itself has a - * restricted range, and fromKey lies outside the + * restricted range, and {@code fromKey} lies outside the * bounds of the range */ - NavigableMap navigableTailMap(K fromKey); + NavigableMap tailMap(K fromKey, boolean inclusive); + + /** + * {@inheritDoc} + * + *

Equivalent to {@code subMap(fromKey, true, toKey, false)}. + * + * @throws ClassCastException {@inheritDoc} + * @throws NullPointerException {@inheritDoc} + * @throws IllegalArgumentException {@inheritDoc} + */ + SortedMap subMap(K fromKey, K toKey); + + /** + * {@inheritDoc} + * + *

Equivalent to {@code headMap(toKey, false)}. + * + * @throws ClassCastException {@inheritDoc} + * @throws NullPointerException {@inheritDoc} + * @throws IllegalArgumentException {@inheritDoc} + */ + SortedMap headMap(K toKey); + + /** + * {@inheritDoc} + * + *

Equivalent to {@code tailMap(fromKey, true)}. + * + * @throws ClassCastException {@inheritDoc} + * @throws NullPointerException {@inheritDoc} + * @throws IllegalArgumentException {@inheritDoc} + */ + SortedMap tailMap(K fromKey); }